1. Field of the Invention
The invention relates to coilers for strip-like material, and more particularly to the underwinding or overwinding of the material onto coiler drums located on opposite sides of a hot reversing mill.
2. Description of the Prior Art
Hot reversing mills for plate and strip having coiler furnaces on opposing sides thereof are employed in semi-continuous mills and as mini-mills for processing metal slabs, such as steel into a hot rolled product.
Conventionally, coilers are operated in one of two ways, either to overwind or underwind the material onto the drum, in which the leading end of the strip is engaged in a slot in the drum, and the drum is rotated in a direction to cause the desired type of winding onto the drum. In such systems, especially in underwinding strip onto the drum, it has been known to provide a tiltable table roll assembly with fixed table roll mountings, which roll assembly in the coiling operation is pivoted upwardly toward the drum either to retain the strip against a portion of the drum, as exemplified in U.S. Pat. Nos. 4,455,848 and 4,485,651; or to convey the leading end of the strip into the slot of the drum or the tailing end of the strip into the mill, as exemplified in U.S. Pat. No. 3,613,426. In an overwinding system, it is conventional to provide a pivotal arm swingable in and out of the furnace and having a single roll assembly for engaging against the periphery and a fixed roll assembly mounted in the furnace for guiding the strip upon its winding onto the mandrel as exemplified in U.S. Pat. No. 2,675,720.
Several problems arise in these known systems, such as overheating of the table rolls, especially the tiltable roll assembly when in its passline positioning or in its positioning adjacent to the drum located in the coiling furnace. The location of the table roll assembly for supporting the strip onto the mandrel and the fact that the table roll assembly of the prior art is fixedly mounted preventing proper orientation of the rolls around the periphery of the mandrel results in slippage of the leading end of the strip from the slot of the drum before the first wrap is completed around the drum; and/or inadequate wrapping of the strip onto the mandrel. The table roll assemblies cooperating with the coiler and the guide rolls in the furnace of the prior art are such that they remain in a fixed position relative to the passline or in the coiler furnace and cannot be easily removed upon repair and maintenance of the coiler, the furnace, or the rolls themselves.